For some time there has been a widespread interest in two-dimensional systems, and in particular, transition metal dichalcogenide layered compounds. This group of materials is usually considered to be two-dimensional because of the high anisotropy resulting from strong bonding within the layers and weak interlayer interactions. Additional interest in layered compounds arises from the fact that they can be intercalated with a variety of metals and compounds.
Exfoliation of the metallic layered compounds TaS.sub.2 and NbS.sub.2 by intercalation of hydrogen and water has been previously reported. U.S. Pat. No. 4,299,892, issued to Martin B. Dines, et al., 1975, discloses amorphous and sheet dichalcogenides of Group IVB, VB, molybdenum and tungsten.
Present methods for preparing restricted types of inclusion compounds consist of the following techniques:
1. Simple intercalation, producing intercalation compounds; PA1 2. Incorporation of certain organic materials during precipitation reactions synthesizing layered materials, as described in the Dines et al. patent, U.S. Pat. No. 4,299,892, column 12, lines 38-40; and PA1 3. Crystal growth at high temperatures. PA1 F. Levy (editor, "Intercalated Layered Materials", Physics and Chemistry of Materials with Layered Structures, Vol. 6 (Reidel, Dordrecht, 1979); PA1 M. B. Dines, Mater. Res. Bull. 10, 287 (1975); PA1 Pourbaix, "Atlas of Electrochemical Equilibria in Aqueous Solutions" (Pergamon, 1966); PA1 D. W. Murphy and G. W. Hull, J. Chem. Phys. 62, 173 (1975).
The applicants are aware of the following references which are more or less relevant to various aspects of this invention: